<template>
  <div class="pagination">
    <button :disabled="pageNo===1">上一页</button>
    <button v-show="startEndPage.start!==1">1</button>

    <button v-show="startEndPage.start>2">···</button>

    <button v-for="page in pageNum" :key="page">{{page}}</button>

    <button v-show="startEndPage.start<totalPages-1">···</button>
    <button v-show="startEndPage.end!==totalPages">{{totalPages}}</button>
    <button :disabled="pageNo===totalPages">下一页</button>

    <button style="margin-left: 30px">共 {{totalPages}} 页</button>
  </div>
</template>

<script>
export default {
  name: "Pagination",
  props:['pageNo','totalPages','continuPage'],
  computed:{
      startEndPage(){
          const{pageNo,totalPages,continuPage} = this
          let start=0, end=0
            if(continuPage>=totalPages){
                start=1,
                end=totalPages
            }else{
                start=pageNo-Math.floor(continuPage/2)
                end=pageNo+Math.floor(continuPage/2)
                if(start<=2){
                    start=1,
                    end=continuPage
                }
                if(end>=totalPages-1){
                    start=totalPages-continuPage+1
                    end=totalPages
                }
            }
          
          return{start,end}
      },
      pageNum(){
          let arr=[]
          for (let i = 1; i <= this.startEndPage.end; i++) {
               if(i>=this.startEndPage.start){
                   arr.push(i)
               }
          }
          return arr
      }
  }
};
</script>

<style lang="less" scoped>
.pagination {
  button {
    margin: 0 5px;
    background-color: #f4f4f5;
    color: #606266;
    outline: none;
    border-radius: 2px;
    padding: 0 4px;
    vertical-align: top;
    display: inline-block;
    font-size: 13px;
    min-width: 35.5px;
    height: 28px;
    line-height: 28px;
    cursor: pointer;
    box-sizing: border-box;
    text-align: center;
    border: 0;

    &[disabled] {
      color: #c0c4cc;
      cursor: not-allowed;
    }

    &.active {
      cursor: not-allowed;
      background-color: #409eff;
      color: #fff;
    }
  }
}
</style>
